ARM64: use 32-bit moves for constants where possible.

If we know that a particular 64-bit constant has all high bits zero, then we
can rely on the fact that 32-bit ARM64 instructions automatically zero out the
high bits of an x-register. This gives the expansion logic less constraints to
satisfy and so sometimes allows it to pick better sequences.

Came up while porting test/CodeGen/AArch64/movw-consts.ll: this will allow a
32-bit MOVN to be used in @test8 soon.

llvm-svn: 206379
diff --git a/llvm/test/CodeGen/ARM64/aapcs.ll b/llvm/test/CodeGen/ARM64/aapcs.ll
index fc1266c..e4889b7 100644
--- a/llvm/test/CodeGen/ARM64/aapcs.ll
+++ b/llvm/test/CodeGen/ARM64/aapcs.ll
@@ -80,7 +80,7 @@
 define void @test_variadic() {
   call void(i32, ...)* @variadic(i32 0, i64 1, double 2.0)
 ; CHECK: fmov d0, #2.0
-; CHECK: orr x1, xzr, #0x1
+; CHECK: orr w1, wzr, #0x1
 ; CHECK: bl variadic
   ret void
 }
diff --git a/llvm/test/CodeGen/ARM64/atomic.ll b/llvm/test/CodeGen/ARM64/atomic.ll
index 4a957b8..13502f4 100644
--- a/llvm/test/CodeGen/ARM64/atomic.ll
+++ b/llvm/test/CodeGen/ARM64/atomic.ll
@@ -17,14 +17,14 @@
 
 define i64 @val_compare_and_swap_64(i64* %p) {
 ; CHECK-LABEL: val_compare_and_swap_64:
-; CHECK: orr    [[NEWVAL_REG:x[0-9]+]], xzr, #0x4
-; CHECK: orr    [[OLDVAL_REG:x[0-9]+]], xzr, #0x7
+; CHECK: orr    w[[NEWVAL_REG:[0-9]+]], wzr, #0x4
+; CHECK: orr    w[[OLDVAL_REG:[0-9]+]], wzr, #0x7
 ; CHECK: [[LABEL:.?LBB[0-9]+_[0-9]+]]:
 ; CHECK: ldxr   [[RESULT:x[0-9]+]], [x0]
-; CHECK: cmp    [[RESULT]], [[OLDVAL_REG]]
+; CHECK: cmp    [[RESULT]], x[[OLDVAL_REG]]
 ; CHECK: b.ne   [[LABEL2:.?LBB[0-9]+_[0-9]+]]
-; CHECK-NOT: stxr [[NEWVAL_REG]], [[NEWVAL_REG]]
-; CHECK: stxr   [[SCRATCH_REG:w[0-9]+]], [[NEWVAL_REG]], [x0]
+; CHECK-NOT: stxr x[[NEWVAL_REG]], x[[NEWVAL_REG]]
+; CHECK: stxr   [[SCRATCH_REG:w[0-9]+]], x[[NEWVAL_REG]], [x0]
 ; CHECK: cbnz   [[SCRATCH_REG]], [[LABEL]]
 ; CHECK: [[LABEL2]]:
   %val = cmpxchg i64* %p, i64 7, i64 4 monotonic monotonic
@@ -47,10 +47,10 @@
 
 define i64 @fetch_and_nand_64(i64* %p) {
 ; CHECK-LABEL: fetch_and_nand_64:
-; CHECK: orr    [[OLDVAL_REG:x[0-9]+]], xzr, #0x7
+; CHECK: orr    w[[OLDVAL_REG:[0-9]+]], wzr, #0x7
 ; CHECK: [[LABEL:.?LBB[0-9]+_[0-9]+]]:
 ; CHECK: ldaxr   [[DEST_REG:x[0-9]+]], [x0]
-; CHECK: bic    [[SCRATCH2_REG:x[0-9]+]], [[OLDVAL_REG]], [[DEST_REG]]
+; CHECK: bic    [[SCRATCH2_REG:x[0-9]+]], x[[OLDVAL_REG]], [[DEST_REG]]
 ; CHECK: stlxr   [[SCRATCH_REG:w[0-9]+]], [[SCRATCH2_REG]], [x0]
 ; CHECK: cbnz   [[SCRATCH_REG]], [[LABEL]]
 ; CHECK: mov    x0, [[DEST_REG]]
@@ -74,10 +74,10 @@
 
 define i64 @fetch_and_or_64(i64* %p) {
 ; CHECK: fetch_and_or_64:
-; CHECK: orr    [[OLDVAL_REG:x[0-9]+]], xzr, #0x7
+; CHECK: orr    w[[OLDVAL_REG:[0-9]+]], wzr, #0x7
 ; CHECK: [[LABEL:.?LBB[0-9]+_[0-9]+]]:
 ; CHECK: ldxr   [[DEST_REG:x[0-9]+]], [x0]
-; CHECK: orr    [[SCRATCH2_REG:x[0-9]+]], [[DEST_REG]], [[OLDVAL_REG]]
+; CHECK: orr    [[SCRATCH2_REG:x[0-9]+]], [[DEST_REG]], x[[OLDVAL_REG]]
 ; CHECK: stxr   [[SCRATCH_REG:w[0-9]+]], [[SCRATCH2_REG]], [x0]
 ; CHECK: cbnz   [[SCRATCH_REG]], [[LABEL]]
 ; CHECK: mov    x0, [[DEST_REG]]
diff --git a/llvm/test/CodeGen/ARM64/bitfield-extract.ll b/llvm/test/CodeGen/ARM64/bitfield-extract.ll
index 96b6967..40dee71 100644
--- a/llvm/test/CodeGen/ARM64/bitfield-extract.ll
+++ b/llvm/test/CodeGen/ARM64/bitfield-extract.ll
@@ -376,10 +376,10 @@
 ; CHECK-LABEL: fct17:
 ; CHECK: ldr [[REG1:x[0-9]+]],
 ; Create the constant
-; CHECK: movz [[REGCST:x[0-9]+]], #26, lsl #16
-; CHECK: movk [[REGCST]], #33120
+; CHECK: movz w[[REGCST:[0-9]+]], #26, lsl #16
+; CHECK: movk w[[REGCST]], #33120
 ; Do the masking
-; CHECK: and [[REG2:x[0-9]+]], [[REG1]], [[REGCST]]
+; CHECK: and [[REG2:x[0-9]+]], [[REG1]], x[[REGCST]]
 ; CHECK-NEXT: bfm [[REG2]], x1, #16, #18
 ; lsr is an alias of ubfm
 ; CHECK-NEXT: ubfm [[REG3:x[0-9]+]], [[REG2]], #2, #61
diff --git a/llvm/test/CodeGen/ARM64/const-addr.ll b/llvm/test/CodeGen/ARM64/const-addr.ll
index c77a6db..977628a 100644
--- a/llvm/test/CodeGen/ARM64/const-addr.ll
+++ b/llvm/test/CodeGen/ARM64/const-addr.ll
@@ -5,8 +5,8 @@
 ; Test if the constant base address gets only materialized once.
 define i32 @test1() nounwind {
 ; CHECK-LABEL:  test1
-; CHECK:        movz  x8, #1039, lsl #16
-; CHECK-NEXT:   movk  x8, #49152
+; CHECK:        movz  w8, #1039, lsl #16
+; CHECK-NEXT:   movk  w8, #49152
 ; CHECK-NEXT:   ldp w9, w10, [x8, #4]
 ; CHECK:        ldr w8, [x8, #12]
   %at = inttoptr i64 68141056 to %T*
diff --git a/llvm/test/CodeGen/ARM64/csel.ll b/llvm/test/CodeGen/ARM64/csel.ll
index cbf1769..d0ee61c 100644
--- a/llvm/test/CodeGen/ARM64/csel.ll
+++ b/llvm/test/CodeGen/ARM64/csel.ll
@@ -126,7 +126,7 @@
 entry:
 ; CHECK-LABEL: foo10:
 ; CHECK: cmp x0, #0
-; CHECK: orr x[[REG:[0-9]+]], xzr, #0x4
+; CHECK: orr w[[REG:[0-9]+]], wzr, #0x4
 ; CHECK: csinv x0, x[[REG]], x[[REG]], ne
   %tobool = icmp ne i64 %v, 0
   %cond = select i1 %tobool, i64 4, i64 -5
@@ -148,7 +148,7 @@
 entry:
 ; CHECK-LABEL: foo12:
 ; CHECK: cmp x0, #0
-; CHECK: orr x[[REG:[0-9]+]], xzr, #0x4
+; CHECK: orr w[[REG:[0-9]+]], wzr, #0x4
 ; CHECK: csneg x0, x[[REG]], x[[REG]], ne
   %tobool = icmp ne i64 %v, 0
   %cond = select i1 %tobool, i64 4, i64 -4
@@ -203,7 +203,7 @@
 entry:
 ; CHECK-LABEL: foo17:
 ; CHECK: cmp x0, x1
-; CHECK: orr x[[REG:[0-9]+]], xzr, #0x1
+; CHECK: orr w[[REG:[0-9]+]], wzr, #0x1
 ; CHECK: csinc x0, x[[REG]], x[[REG]], le
   %cmp = icmp sgt i64 %a, %b
   %. = select i1 %cmp, i64 2, i64 1
@@ -214,7 +214,7 @@
 entry:
 ; CHECK-LABEL: foo18:
 ; CHECK: cmp x0, x1
-; CHECK: orr x[[REG:[0-9]+]], xzr, #0x1
+; CHECK: orr w[[REG:[0-9]+]], wzr, #0x1
 ; CHECK: csinc x0, x[[REG]], x[[REG]], gt
   %cmp = icmp sgt i64 %a, %b
   %. = select i1 %cmp, i64 1, i64 2
diff --git a/llvm/test/CodeGen/ARM64/long-shift.ll b/llvm/test/CodeGen/ARM64/long-shift.ll
index 6f37044..caa486a 100644
--- a/llvm/test/CodeGen/ARM64/long-shift.ll
+++ b/llvm/test/CodeGen/ARM64/long-shift.ll
@@ -3,8 +3,8 @@
 define i128 @shl(i128 %r, i128 %s) nounwind readnone {
 ; CHECK-LABEL: shl:
 ; CHECK: lslv  [[XREG_0:x[0-9]+]], x1, x2
-; CHECK-NEXT: orr [[XREG_1:x[0-9]+]], xzr, #0x40
-; CHECK-NEXT: sub [[XREG_2:x[0-9]+]], [[XREG_1]], x2
+; CHECK-NEXT: orr w[[XREG_1:[0-9]+]], wzr, #0x40
+; CHECK-NEXT: sub [[XREG_2:x[0-9]+]], x[[XREG_1]], x2
 ; CHECK-NEXT: lsrv  [[XREG_3:x[0-9]+]], x0, [[XREG_2]]
 ; CHECK-NEXT: orr [[XREG_6:x[0-9]+]], [[XREG_3]], [[XREG_0]]
 ; CHECK-NEXT: sub [[XREG_4:x[0-9]+]], x2, #64
@@ -20,10 +20,10 @@
 }
 
 define i128 @ashr(i128 %r, i128 %s) nounwind readnone {
-; CHECK: ashr:
+; CHECK-LABEL: ashr:
 ; CHECK: lsrv  [[XREG_0:x[0-9]+]], x0, x2
-; CHECK-NEXT: orr [[XREG_1:x[0-9]+]], xzr, #0x40
-; CHECK-NEXT: sub [[XREG_2:x[0-9]+]], [[XREG_1]], x2
+; CHECK-NEXT: orr w[[XREG_1:[0-9]+]], wzr, #0x40
+; CHECK-NEXT: sub [[XREG_2:x[0-9]+]], x[[XREG_1]], x2
 ; CHECK-NEXT: lslv  [[XREG_3:x[0-9]+]], x1, [[XREG_2]]
 ; CHECK-NEXT: orr [[XREG_4:x[0-9]+]], [[XREG_0]], [[XREG_3]]
 ; CHECK-NEXT: sub [[XREG_5:x[0-9]+]], x2, #64
@@ -40,10 +40,10 @@
 }
 
 define i128 @lshr(i128 %r, i128 %s) nounwind readnone {
-; CHECK: lshr:
+; CHECK-LABEL: lshr:
 ; CHECK: lsrv  [[XREG_0:x[0-9]+]], x0, x2
-; CHECK-NEXT: orr [[XREG_1:x[0-9]+]], xzr, #0x40
-; CHECK-NEXT: sub [[XREG_2:x[0-9]+]], [[XREG_1]], x2
+; CHECK-NEXT: orr w[[XREG_1:[0-9]+]], wzr, #0x40
+; CHECK-NEXT: sub [[XREG_2:x[0-9]+]], x[[XREG_1]], x2
 ; CHECK-NEXT: lslv  [[XREG_3:x[0-9]+]], x1, [[XREG_2]]
 ; CHECK-NEXT: orr [[XREG_4:x[0-9]+]], [[XREG_0]], [[XREG_3]]
 ; CHECK-NEXT: sub [[XREG_5:x[0-9]+]], x2, #64
diff --git a/llvm/test/CodeGen/ARM64/patchpoint.ll b/llvm/test/CodeGen/ARM64/patchpoint.ll
index 9e5ed6f..dd555b0 100644
--- a/llvm/test/CodeGen/ARM64/patchpoint.ll
+++ b/llvm/test/CodeGen/ARM64/patchpoint.ll
@@ -67,11 +67,11 @@
 entry:
 ; CHECK-LABEL: jscall_patchpoint_codegen2:
 ; CHECK:      Ltmp
-; CHECK:      orr x{{.+}}, xzr, #0x6
+; CHECK:      orr w{{.+}}, wzr, #0x6
 ; CHECK-NEXT: str x{{.+}}, [sp, #24]
 ; CHECK-NEXT: orr w{{.+}}, wzr, #0x4
 ; CHECK-NEXT: str w{{.+}}, [sp, #16]
-; CHECK-NEXT: orr x{{.+}}, xzr, #0x2
+; CHECK-NEXT: orr w{{.+}}, wzr, #0x2
 ; CHECK-NEXT: str x{{.+}}, [sp]
 ; CHECK:      Ltmp
 ; CHECK-NEXT: movz  x16, #65535, lsl #32
@@ -88,15 +88,15 @@
 entry:
 ; CHECK-LABEL: jscall_patchpoint_codegen3:
 ; CHECK:      Ltmp
-; CHECK:      movz  x{{.+}}, #10
+; CHECK:      movz  w{{.+}}, #10
 ; CHECK-NEXT: str x{{.+}}, [sp, #48]
 ; CHECK-NEXT: orr w{{.+}}, wzr, #0x8
 ; CHECK-NEXT: str w{{.+}}, [sp, #36]
-; CHECK-NEXT: orr x{{.+}}, xzr, #0x6
+; CHECK-NEXT: orr w{{.+}}, wzr, #0x6
 ; CHECK-NEXT: str x{{.+}}, [sp, #24]
 ; CHECK-NEXT: orr w{{.+}}, wzr, #0x4
 ; CHECK-NEXT: str w{{.+}}, [sp, #16]
-; CHECK-NEXT: orr x{{.+}}, xzr, #0x2
+; CHECK-NEXT: orr w{{.+}}, wzr, #0x2
 ; CHECK-NEXT: str x{{.+}}, [sp]
 ; CHECK:      Ltmp
 ; CHECK-NEXT: movz  x16, #65535, lsl #32